1. Field of the Invention
The present invention relates to a content delivery apparatus and a content delivery method using the same, and more specifically to a technique for acquiring content from an origin server computer storing content and delivering the acquired content to a client computer in accordance with a delivery request from the client computer.
2. Description of Related Art
Content delivery service, where content data, which is video/audio data that has been compressed and coded, is delivered by streaming in response to a request from a client, has been rapidly becoming popular.
Reference 1 discloses a cache server provided between a media server and a client. Specifically, in reference 1, when a delivery request for delivering a certain media file is issued from the client to the media server, the cache server receives the delivery request and delivers the relevant media file, which has been cached, by streaming. If the relevant media file has not been cached in the cache server, the media server delivers the media file to the client by streaming, and the cache server acquires the relevant media file at the same time (see reference 1; JP2003-153229 A).
Due to the rapid diffusion of the content delivery services these days, a need for a content delivery apparatus capable of simultaneously delivering plural pieces of content has increased.
However, capacity for delivering content by streaming per one server computer serving as the content delivery apparatus is limited, so receiving more delivery requests at the same time requires an increase in the number of server computers, and that results in an increase of cost.
In addition, the maximum permissible power per floor on which the server computers are provided needs to be taken into consideration and the power consumption of the server computers needs to be kept low in view of environmental issues these days, so it is difficult to simply increase the number of server computers.